Deficient Regulatory T Cell Activity and Low Frequency of IL-17-Producing T Cells Correlate with the Extent of Cardiomyopathy in Human Chagas' Disease

et al. (2012) Deficient Regulatory T Cell Activity and Low Frequency of IL-17- Producing T Cells Correlate with the Extent of Cardiomyopathy in Human Chagas' Disease. PLoS Negl Trop Dis 6(4): e1630. doi:10.1371/journal.pntd.0001630 Deficient Regulatory T Cell Activity and Low Frequency of IL-17-Producing T Cells Correlate with the Extent of Cardiomyopathy in Human Chagas' Disease Paulo Marcos Matta Guedes 0 Fredy Roberto Salazar Gutierrez 0 Grace Kelly Silva 0 Renata Dellalibera-Joviliano 0 Gerson Jhonatan Rodrigues 0 Lusiane Maria Bendhack 0 Anis Rassi Jr. 0 Anis Rassi 0 Andre Schmidt 0 Benedito Carlos Maciel 0 Jose Antonio Marin Neto 0 Joa o Santana Silva 0 Ricardo T. Gazzinelli, University of Massachusetts Medical School, United States of America 0 1 Department of Microbiology and Parasitology, Federal University of Rio Grande do Norte, Natal, Brazil, 2 Department of Biochemistry and Immunology, School of Medicine of Ribeira o Preto, University of Sa o Paulo , Sa o Paulo , Brazil , 3 School of Medicine, University Antonio Narino, Bogota, Colombia, 4 Integrated Faculty Fafibe and Department of Surgery and Anatomy, School of Medicine of Ribeira o Preto, University of Sa o Paulo , Sa o Paulo , Brazil , 5 Department of Pharmacology, School of Medicine of Ribeira o Preto, University of Sa o Paulo , Sa o Paulo , Brazil , 6 Department of Physical and Chemistry, School of Pharmaceutical Sciences of Ribeira o Preto, University of Sa o Paulo , Sa o Paulo , Brazil , 7 Division of Cardiology, Anis Rassi Hospital , Goiania , Brazil , 8 Division of Cardiology, School of Medicine of Ribeira o Preto, University of Sa o Paulo , Sa o Paulo , Brazil Background: Myocardium damage during Chagas' disease results from the immunological imbalance between pro- and production of anti-inflammatory cytokines and has been explained based on the Th1-Th2 dichotomy and regulatory T cell activity. Recently, we demonstrated that IL-17 produced during experimental T. cruzi infection regulates Th1 cells differentiation and parasite induced myocarditis. Here, we investigated the role of IL-17 and regulatory T cell during human Chagas' disease. Methodology/Principal Findings: First, we observed CD4+IL-17+ T cells in culture of peripheral blood mononuclear cells (PBMC) from Chagas' disease patients and we evaluated Th1, Th2, Th17 cytokine profile production in the PBMC cells from Chagas' disease patients (cardiomyopathy-free, and with mild, moderate or severe cardiomyopathy) cultured with T. cruzi antigen. Cultures of PBMC from patients with moderate and severe cardiomyopathy produced high levels of TNF-a, IFN-c and low levels of IL-10, when compared to mild cardiomyopathy or cardiomyopathy-free patients. Flow cytometry analysis showed higher CD4+IL-17+ cells in PBMC cultured from patients without or with mild cardiomyopathy, in comparison to patients with moderate or severe cardiomyopathy. We then analyzed the presence and function of regulatory T cells in all patients. All groups of Chagas' disease patients presented the same frequency of CD4+CD25+ regulatory T cells. However, CD4+CD25+ T cells from patients with mild cardiomyopathy or cardiomyopathy-free showed higher suppressive activity than those with moderate and severe cardiomyopathy. IFN-c levels during chronic Chagas' disease are inversely correlated to the LVEF (P = 0.007, r = 20.614), while regulatory T cell activity is directly correlated with LVEF (P = 0.022, r = 0.500). Conclusion/Significance: These results indicate that reduced production of the cytokines IL-10 and IL-17 in association with high levels of IFN-c and TNF-a is correlated with the severity of the Chagas' disease cardiomyopathy, and the immunological imbalance observed may be causally related with deficient suppressor activity of regulatory T cells that controls myocardial inflammation. - Funding: This work was supported by Fundacao de Amparo a` Pesquisa do Estado de Sao Paulo (FAPESP), The Millennium Institute for Vaccine Development and Technology (CNPq) and Coordenacao de Aperfeicoamento de Pessoal de Nvel Superior (CAPES). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. . These authors contributed equally to this work. Introduction At the present time, about 7.7 million people are infected and 28 million are at risk of being infected with Trypanosoma cruzi in Central and South America [13]. This hemoflagellate protozoan is the etiological agent of Chagas disease. Most of the infected individuals remain asymptomatic during chronic infection (60 70%), characterizing the indeterminate form of the disease. Conversely, 3040% of chronically infected patients progress to cardiac and/or digestive pathologic involvement [4,5], and prognostic markers for heart disease progression are required. A balanced immune response during T. cruzi infection is critical to control the parasite burden in heart and digestive tissues [6,7]. Production of pro-inflammatory cytokines is required for activation of the effector T lymphocytes responses and is associated with Dilated cardiomyopathy is one of the clinical forms of Chagas disease (CD) after the infection caused by the parasite Trypanosoma cruzi. Even though strategies adopted in most Latin-American countries in the last decades towards vector control have been effective in reducing the incidence of CD, active transmission is maintained in some regions, and secondary prevention approaches are still required for the infected patients, mostly because the specific anti-parasitic medications are toxic and perhaps of limited efficacy in chronically infected individuals. Moreover, there are no markers to predict the risk of developing dilated cardiomyopathy in asymptomatic, chronically infected patients, although the failure in the mechanisms that control the immune response can be involved in the development of Chagas heart disease. In this study we show that preserved activity of regulatory T cells and the production of the cytokine IL-17 are connected with a more benign evolution of the disease, which brings a new understanding on the mechanisms associated with progression of CD. the pathogenesis of Chagas disease cardiomyopathy (CC), while regulatory cytokines (mainly IL-10) are related to protection [8,9]. Peripheral blood mononuclear cells (PBMC) from patients with CC produce more IFN-c, TNF-a and IL-6, and less IL-4 and IL10, compared to individuals with the indeterminate form of the disease [1,3,7,1014]. However, other studies failed to demonstrate any correlation between production of Th1 and Th2 cytokines profile and the clinical stages of Chagas disease [15], being that further investigations to elucidate such mechanisms are necessary, one aim of this work. Regulatory T cells (Treg) are an important source of regulatory cytokines and are involved in the control of t (...truncated)